Quiescent Time Research Articles

Influence of atmospheric state on variability of long-term residual ambient sound level measurements in a subalpine valley.

Two natural influences on the acoustic environments of mountainous parks and communities are flowing water and shifting weather. A central purpose of the acoustic measurement design used by the United States National Park Service is to provide spectral estimates of residual ambient sound level metrics at a seasonal time scale. Acoustic monitoring sampling methodologies are often designed using a sequence of similar measurements. When source and residual ambient spectra overlap, an estimate of variability in the latter is beneficial to successful monitoring design. The observed and modelled effects of atmospheric state on sound level are analyzed to reveal variability due to these effects at a long-term monitoring site in Denali National Park, Alaska. The analysis of variability incorporates a covariate that is otherwise challenging to estimate in remote settings: vertical temperature gradients in the atmospheric boundary layer. Results reveal inversions (positive gradients) in the atmosphere ≥30% between 19:00 and 09:00. Inversion strengths above 0.06 °C/m are associated with 10-15 dB increases in sound level over hourly time scales. Because inversions tend to occur during otherwise quiescent times of day, they ultimately reduce seasonal variability at the site and corresponding uncertainty in noise metrics for transportation noise arriving from varied directions.

Antidepressant Effect and Mechanism of Picea mariana Essential Oil on Reserpine-Induced Depression Model Mice.

The disturbance of brain biochemical substances serves as a primary cause and aggravating factor of depression. This study aimed to investigate the principal components of Picea mariana and its effect on reserpine-induced depression mice,w ith its relationship with brain central transmitters and related proteins. The main constituents of P. mariana essential oil (PMEO) were analyzed by GC-MS spectrometry. The quiescent time in the tail suspension test (TST) and forced swim test (FST), along with the weight change of the mice was detected. The number of normal neurons was quantified through Nissl staining. Immunohistochemistry was employed to determine the levels of 5HT-1A and 5HT-2A in the brain. Western blotting was utilized to detect 5HT-2A, CRF and TrkB protein levels. RT-qPCR was used to detect the mRNA levels of 5HT-1A, 5HT-2A, TrkB, CRF, and BDNF. The main active ingredients of PMEOs were (-) -bornyl acetate (44.95%), γ-Terpinene (14.17%), and β-Pinene (10.12%). PMEOs effectively improved the retardation and weight loss due to anorexia in depression-like mice. This improvement was associated with an increase in the number of normal neurons. After administering different doses of PMEOs, the levels of 5HT-1A, 5HT-2A, CRF, and TrkB were found to be increased in brain tissue. RT-qPCR revealed that the mRNA levels of CRF, 5HT-1A, and 5HT-2A were generally upregulated, whereas TrkB and BDNF were downregulated. PMEO can effectively alleviate depression induced by reserpine, which may be attributed to its regulation of 5HT-1A, 5HT-2A, CRF and TrkB protein expression, thus reducing brain nerve injury.

Thermal Evolution of an Active Region Through Quiet and Flaring Phases as Observed by NuSTAR, XRT, and AIA

Solar active regions (ARs) contain a broad range of temperatures, with the thermal plasma distribution often observed to peak in the few millions of kelvin. Differential emission measure (DEM) analysis can allow instruments with diverse temperature responses to be used in concert to estimate this distribution. Nuclear Spectroscopic Telescope ARray (NuSTAR) hard X-ray (HXR) observations are uniquely sensitive to the highest-temperature components of the corona, and thus extremely powerful for examining signatures of reconnection-driven heating. Here, we use NuSTAR diagnostics in combination with extreme-ultraviolet and soft X-ray observations (from the Solar Dynamics Observatory/Atmospheric Imaging Assembly and Hinode/X-Ray Telescope) to construct DEMs over 170 distinct time intervals during a 5 hr observation of an alternately flaring and quiet active region (NOAA designation AR 12712). This represents the first HXR study to examine the time evolution of the distribution of thermal plasma in an AR. During microflares, we find that the initial microflare-associated plasma heating is predominantly heating of material that is already relatively hot, followed later on by broader heating of initially cooler material. During quiescent times, we show that the amount of extremely hot (>10 MK) material in this region is significantly (∼2–4 orders of magnitude) less than that found in the quiescent AR observed in HXRs by FOXSI-2. This result implies there can be radically different high-temperature thermal distributions in different ARs, and strongly motivates future HXR DEM studies covering a large number of these regions.

Initial nutrient condition determines the recovery speed of quiescent cells in fission yeast

Most of microbe cells spend the majority of their times in quiescence due to unfavorable environmental conditions. The study of this dominant state is crucial for understanding the basic cell physiology. Retained recovery ability is a critical property of quiescent cells, which consists of two features: how long the cells can survive (the survivability) and how fast they can recover (the recovery activity). While the survivability has been extensively studied under the background of chronological aging, how the recovery activity depends on the quiescent time and what factors influence its dynamics have not been addressed quantitatively. In this work, we systematically quantified both the survivability and the recovery activity of long-lived quiescent fission yeast cells at the single cell level under various nutrient conditions. It provides the most profound evolutionary dynamics of quiescent cell regeneration ability described to date. We found that the single cell recovery time linearly increased with the starvation time before the survivability significantly declined. This linearity was robust under various nutrient conditions and the recovery speed was predetermined by the initial nutrient condition. Transcriptome profiling further revealed that quiescence states under different nutrient conditions evolve in a common trajectory but with different speed. Our results demonstrated that cellular quiescence has a continuous spectrum of depths and its physiology is greatly influenced by environmental conditions.

Signatures of the Self-organized Criticality Phenomenon in Precursors of Gamma-Ray Bursts

Precursors provide important clues to the nature of gamma-ray burst (GRB) central engines and can be used to contain GRB physical processes. In this Letter, we study the self-organized criticality in precursors of long GRBs in the third Swift/Burst Alert Telescope catalog. We investigate the differential and cumulative size distributions of 100 precursors, including peak flux, duration, rise time, decay time, and quiescent time with the Markov Chain Monte Carlo technique. It is found that all of the distributions can be well described by power-law models and understood within the physical framework of a self-organized criticality system. In addition, we inspect the cumulative distribution functions of the size differences with a q-Gaussian function. The scale-invariance structures of precursors further strengthen our findings. Particularly, similar analyses are made in 127 main bursts. The results show that both precursors and main bursts can be attributed to a self-organized criticality system with the spatial dimension S = 3 and driven by a similar magnetically dominated process.

A comparative experimental study on the influence of bottleneck width on evacuation characteristics of pedestrian flow in funnel shape bottleneck and normal bottleneck

Previous studies have proposed that increasing bottleneck width help increase evacuation efficiency in normal bottleneck evacuation. However, the effect of funnel shape bottleneck coupled with bottleneck width on evacuation efficiency is still unknown. To improve the understanding of the influence of bottleneck width in funnel shape bottleneck evacuation on the movement characteristics of pedestrians, the funnel shape bottleneck evacuation experiment is carried out in this study. The movement characteristics of pedestrians passing through the funnel shape bottleneck versus the normal bottleneck are compared from the aspects of trajectories, fundamental diagrams, density profiles, speed distribution, flow, time interval, and quiescent time. Logarithmic function fits the relation between density and speed well both for funnel shape bottleneck and for normal bottleneck evacuation. Under the same density, the funnel shape bottleneck allows pedestrians to move faster than the normal bottleneck. For the same bottleneck width, the density in the funnel shape bottleneck is smaller than that in the normal bottleneck. The flow increases linearly with the increasing bottleneck width both in funnel shape bottleneck and in the normal bottleneck. When the bottleneck width is smaller than 1.31 m, the flow of funnel shape bottleneck is higher than that of the normal bottleneck. The funnel shape bottleneck reduces the occurrence and the lasting time of quiescent behaviors. The evacuation time decreases piecewise linearly with the increasing bottleneck width both for the funnel shape bottleneck and the normal bottleneck. The comparisons reveal that the funnel shape bottleneck increases evacuation efficiency under the smaller bottleneck width. The results obtained in this study describe the difference between the funnel shape bottleneck and the normal bottleneck, which is beneficial to safety managers and pedestrian facilities designers.

Specific mating behavior of Malayan pangolin (Manis javanica) in captivity

Pangolin is a mysterious animal in the Family Pholidota, Mammalia. Malayan pangolin (Manis javanica) is one of eight existing species and is listed in Manis. With the number of wild pangolins (Manis spp.) rapidly decreasing, captive breeding has become an important way to protect them from extinction. The research on mating behavior of pangolins is an important content to understand its reproductive characteristics and develop breeding management. From 2016 to 2022, a total of 360 mating events were observed in six males and 24 females through closed circuit television (CCTV) surveillance. The results show that males do not engage in complex courtship behavior before mating. In addition, we found that male pangolins adopted a ventrolateral mating position. Once males selected the side (left/right) of the female pangolin from which to approach to mate, they usually remained on the same side for subsequent mating, suggesting that male pangolins may have a preference in mating position. Finally, all mating events were observed at 1.72 ± 1.47 (n = 83, Mean ± SD) days after cohabitation and adjustment time before mating (from the male touching the female to intromission) took 4.98 ± 3.86 mins (n = 323). During mating, males hugged females and remained still for 47.37 ± 10.08 seconds (n = 323), which is the ejaculation and post-ejaculation quiescent time. Remarkably, we observed for the first time two peak mating times, 19:00 to 22:00 and 1:00 to 3:00, suggesting that they may have a preference for mating times. This study provides new insight into the mating behavior of M. javanica and contributes to the development of scientific conservation measures to improve the reproductive capacity of M. javanica.

Merger Signatures are Common, but not Universal, in Massive, Recently Quenched Galaxies at z ∼ 0.7

We present visual classifications of merger-induced tidal disturbances in 143 M * ∼ 1011 M ⊙ post-starburst galaxies at z ∼ 0.7 identified in the Sample. This sample spectroscopically selects galaxies from the Sloan Digital Sky Survey that have stopped their primary epoch of star formation within the past ∼500 Myr. Visual classifications are performed on Hyper Suprime-Cam imaging. We compare to a control sample of mass- and redshift-matched star-forming and quiescent galaxies from the Large Early Galaxy Census and find that post-starburst galaxies are more likely to be classified as disturbed than either category. This corresponds to a factor of times the disturbance rate of older quiescent galaxies and times the disturbance rate of star-forming galaxies. Assuming tidal features persist for ≲500 Myr, this suggests merging is coincident with quenching in a significant fraction of these post-starbursts. Galaxies with tidal disturbances are younger on average than undisturbed post-starburst galaxies in our sample, suggesting tidal features from a major merger may have faded over time. This may be exacerbated by the fact that, on average, the undisturbed subset is fainter, rendering low-surface-brightness tidal features harder to identify. However, the presence of 10 young (≲150 Myr since quenching) undisturbed galaxies suggests that major mergers are not the only fast physical mechanism that shut down the primary epoch of star formation in massive galaxies at intermediate redshift.

Importance of lower atmospheric forcing and magnetosphere-ionosphere coupling in simulating neutral density during the February 2016 geomagnetic storm

During geomagnetic storms a large amount of energy is transferred into the ionosphere-thermosphere (IT) system, leading to local and global changes in e.g., the dynamics, composition, and neutral density. The more steady energy from the lower atmosphere into the IT system is in general much smaller than the energy input from the magnetosphere, especially during geomagnetic storms, and therefore details of the lower atmosphere forcing are often neglected in storm time simulations. In this study we compare the neutral density observed by Swarm-C during the moderate geomagnetic storm of 31 January to 3 February 2016 with the Thermosphere-Ionosphere-Electrodynamics-GCM (TIEGCM) finding that the model can capture the observed large scale neutral density variations better in the southern than northern hemisphere. The importance of more realistic lower atmospheric (LB) variations as specified by the Whole Atmosphere Community Climate Model eXtended (WACCM-X) with specified dynamics (SD) is demonstrated by improving especially the northern hemisphere neutral density by up to 15% compared to using climatological LB forcing. Further analysis highlights the importance of the background atmospheric condition in facilitating hemispheric different neutral density changes in response to the LB perturbations. In comparison, employing observationally based field-aligned current (FAC) versus using an empirical model to describe magnetosphere-ionosphere (MI) coupling leads to an 7–20% improved northern hemisphere neutral density. The results highlight the importance of the lower atmospheric variations and high latitude forcing in simulating the absolute large scale neutral density especially the hemispheric differences. However, focusing on the storm time variation with respect to the quiescent time, the lower atmospheric influence is reduced to 1–1.5% improvement with respect to the total observed neutral density. The results provide some guidance on the importance of more realistic upper boundary forcing and lower atmospheric variations when modeling large scale, absolute and relative neutral density variations.

Percolating transition from weak to strong turbulence in wind-induced water surface waves

Recent studies in hydrodynamic flows and nonlinear plasma waves have demonstrated the turbulent transitions from ordered laminar flows and ordered plane waves, respectively, with the formation of a large percolating turbulent cluster, after the sporadic emergence and decay of turbulent puffs in the spatiotemporal space. These transitions follow the similar order–disorder transition scenario in nonequilibrium extended systems, governed by percolation theory. Here, we experimentally investigate the unexplored issue of whether a similar transition scenario can be extended to wind-driven water waves, especially for the transition from weak to strong turbulent states. Localized sites in the y–t (y is normal to the wind direction) space are binarized into hot turbulent sites (HTSs) and cold turbulent sites depending on the instantaneous energy of the local wave height fluctuations. It is found that increasing the fetch (the distance x from the wind entrance) as increasing the effective drive leads to the transition from the weak to the strong turbulent state with a smooth rapid rise of the area fraction occupied by HTSs, and the formation of a large HTS cluster percolating through the y–t space after the sporadic emergence of HTS clusters. This generic transition behavior and the scaling exponents of the HTS fraction around the critical (percolating) fetch, and of the quiescent time and the quiescent distance between adjacent HTS clusters at the critical fetch, are akin to those around and at the critical point, respectively, for the 1 + 1D (dimensional) nonequilibrium system governed by the directed percolation theory.

Black Hole to Photosphere: 3D GRMHD Simulations of Collapsars Reveal Wobbling and Hybrid Composition Jets

Long-duration γ-ray bursts (GRBs) accompany the collapse of massive stars and carry information about the central engine. However, no 3D models have been able to follow these jets from their birth via black hole (BH) to the photosphere. We present the first such 3D general-relativity magnetohydrodynamic simulations, which span over six orders of magnitude in space and time. The collapsing stellar envelope forms an accretion disk, which drags inwardly the magnetic flux that accumulates around the BH, becomes dynamically important, and launches bipolar jets. The jets reach the photosphere at ∼1012 cm with an opening angle θ j ∼ 6° and a Lorentz factor Γ j ≲ 30, unbinding ≳90% of the star. We find that (i) the disk–jet system spontaneously develops misalignment relative to the BH rotational axis. As a result, the jet wobbles with an angle θ t ∼ 12°, which can naturally explain quiescent times in GRB lightcurves. The effective opening angle for detection θ j + θ t suggests that the intrinsic GRB rate is lower by an order of magnitude than standard estimates. This suggests that successful GRBs are rarer than currently thought and emerge in only ∼0.1% of supernovae Ib/c, implying that jets are either not launched or choked inside most supernova Ib/c progenitors. (ii) The magnetic energy in the jet decreases due to mixing with the star, resulting in jets with a hybrid composition of magnetic and thermal components at the photosphere, where ∼10% of the gas maintains magnetization σ ≳ 0.1. This indicates that both a photospheric component and reconnection may play a role in the prompt emission.

Temporal Analysis of GRB Precursors in the Third Swift-BAT Catalog

Abstract We select 52 long gamma-ray bursts (GRBs) that have precursor activity in the third Swift-BAT catalog. Each episode shown in both the precursors and the main bursts is fitted by the Norris function. We systematically analyze the temporal properties for both the precursors and the main bursts. We do not find any significant difference between the temporal profile of the precursor and that of the main burst. The photon count of the precursor is related to that of the main burst. It is indicated that the precursor and the main burst might have the same physical origin, as the precursor and the main burst follow the same τ p –ω relation. However, we do not find the explicit relation between the energy release of the precursor and the quiescent time. Some theoretical models, such as the fallback collapsar scenario and the jet-cocoon scenario, may be helpful to explain the GRB-precursor phenomena.

Can auxiliary indicators improve COVID-19 forecasting and hotspot prediction?

Short-term forecasts of traditional streams from public health reporting (such as cases, hospitalizations, and deaths) are a key input to public health decision-making during a pandemic. Since early 2020, our research group has worked with data partners to collect, curate, and make publicly available numerous real-time COVID-19 indicators, providing multiple views of pandemic activity in the United States. This paper studies the utility of five such indicators-derived from deidentified medical insurance claims, self-reported symptoms from online surveys, and COVID-related Google search activity-from a forecasting perspective. For each indicator, we ask whether its inclusion in an autoregressive (AR) model leads to improved predictive accuracy relative to the same model excluding it. Such an AR model, without external features, is already competitive with many top COVID-19 forecasting models in use today. Our analysis reveals that 1) inclusion of each of these five indicators improves on the overall predictive accuracy of the AR model; 2) predictive gains are in general most pronounced during times in which COVID cases are trending in "flat" or "down" directions; and 3) one indicator, based on Google searches, seems to be particularly helpful during "up" trends.

Experimental Study on the Transition between Static and Kinetic Frictions of Steel/Shale Pairs

The transition between static and kinetic frictions of steel/shale pairs has been studied. It was found that the coefficient of friction decreased exponentially from static to dynamic friction coefficient with increasing sliding displacement. The difference between static and dynamic friction coefficients and the critical distance Dc under the dry friction condition is much larger than that under the lubricated condition. The transition from static to dynamic friction coefficient is greatly affected by the normal load, quiescent time, and sliding velocity, especially the lubricating condition. Maintaining continuous lubrication of the contact area by the lubricant is crucial to reduce or eliminate the stick-slip motion. The results provide an insight into the transition from static to dynamic friction of steel/shale pairs.

Identification of gamma-ray burst precursors in Fermi-GBM bursts

We present an analysis of more than 11 years of Fermi-GBM data in which 217 Gamma-Ray Bursts (GRBs) are found for which their main burst is preceded by a precursor flash. We find that short GRBs ($<$2 s) are ~10 times less likely to produce a precursor than long GRBs. The quiescent time profile is well described by a double Gaussian distribution, indicating that the observed precursors have two distinct physical progenitors. The light curves of the identified precursor GRBs are publicly available in an online catalog (https://icecube.wisc.edu/~grbweb_public/Precursors.html).

The corona of GJ 1151 in the context of star–planet interaction

ABSTRACT The low-mass star GJ 1151 has been reported to display variable low-frequency radio emission, which has been interpreted as a signpost of coronal star–planet interactions with an unseen exoplanet. Here we report the first X-ray detection of GJ 1151’s corona based on the XMM–Newton data. We find that the star displays a small flare during the X-ray observation. Averaged over the observation, we detect the star with a low coronal temperature of 1.6 MK and an X-ray luminosity of LX = 5.5 × 1026 erg s−1. During the quiescent time periods excluding the flare, the star remains undetected with an upper limit of $L_{\mathrm{ X},\, \mathrm{ qui}} \le 3.7\times 10^{26}$ erg s−1. This is compatible with the coronal assumptions used in a recently published model for a star–planet interaction origin of the observed radio signals from this star.

Interevent Seismicity Statistics Associated With the 2018 Quasiperiodic Collapse Events at Kīlauea, HI, USA

AbstractFollowing the Mw 6.9 Hawaiian earthquake on 4 May 2018, a remarkable quasiperiodic sequence of collapse events began at Halema'uma'u Crater at the summit of Kīlauea Volcano. The collapse events were associated with the drainage of magma from beneath the summit to the Lower East Rift Zone where fissure eruptions occurred. From 4 June 2018 to 2 August 2018 forty‐seven collapse events Mw 5.3 ± 0.1 occurred with the same temporal pattern of seismicity occurring between sequential pairs of collapse events. This paper focuses on this interevent seismicity pattern. Following a collapse event, there was a relatively quiescent period. This was followed by a sudden increase in seismicity, occurring at a nearly linear rate of 397 ± 96 earthquakes per day. These seismically active periods lasted until the next collapse event occurred. The pattern then repeated itself beginning again with postcollapse quiescence. We provide a statistical summary of this seismicity behavior by isolating the quiescent and active times to look at immediate precollapse and postcollapse activity. In mid‐June there were significant changes in the quiescent time lengths (decreased), the number of earthquakes during the interevent times (increased), and the rates of seismicity during the active times (increased). This type of interevent study could be conducted with other seismically well recorded, sequential caldera collapse events and also with other data types to look for potential physical explanations and an improved understanding of precollapse and postcollapse activity.

Precursors in Short Gamma-Ray Bursts as a Possible Probe of Progenitors

Abstract We extract 18 candidate short gamma-ray bursts (SGRBs) with precursors from 660 SGRBs observed by the Fermi and Swift satellites, and carry out a comprehensive analysis of their temporal and spectral features. We obtain the following results: (1) for a large fraction of candidates, the main burst durations are longer than their precursor durations, comparable to their quiescent times from the end of precursors to the beginning of their main bursts. (2) The average flux of precursors tends to increase as their main bursts brighten. (3) As seen from the distributions of hardness ratio and spectral fitting, the precursors are slightly spectrally softer with respect to the main bursts. Moreover, a significant portion of precursors and all main bursts favor a non-thermal spectrum. (4) The precursors might be a probe of the progenitor properties of SGRBs such as the magnetic field strength and the crustal equation of state if they arise from some processes before mergers of binary compact objects rather than post-merger processes.

First ALMA Millimeter-wavelength Maps of Jupiter, with a Multiwavelength Study of Convection

Abstract We obtained the first maps of Jupiter at 1–3 mm wavelength with the Atacama Large Millimeter/Submillimeter Array (ALMA) on 2017 January 3–5, just days after an energetic eruption at 16.°5S jovigraphic latitude had been reported by the amateur community, and about two to three months after the detection of similarly energetic eruptions in the northern hemisphere, at 22.°2–23.°0N. Our observations, probing below the ammonia cloud deck, show that the erupting plumes in the South Equatorial Belt bring up ammonia gas from the deep atmosphere. While models of plume eruptions that are triggered at the water condensation level explain data taken at uv–visible and mid-infrared wavelengths, our ALMA observations provide a crucial, hitherto missing, link in the moist convection theory by showing that ammonia gas from the deep atmosphere is indeed brought up in these plumes. Contemporaneous Hubble Space Telescope data show that the plumes reach altitudes as high as the tropopause. We suggest that the plumes at 22.°2–23.°0N also rise up well above the ammonia cloud deck and that descending air may dry the neighboring belts even more than in quiescent times, which would explain our observations in the north.

Termination of Action Potential Due to Site Selective Ion Channel Blockers

Here, we have provided a qualitative theoretical description about how the action potential generation and its associated intrinsic properties such as ionic current, spiking frequency, action potential duration, gating dynamics, etc. are affected due to site selective ion channel blockers, by suitably adapting Gillespie’s stochastic simulation technique to an extended Hodgkin–Huxley Markov model, representing a very basic type of neuron. Considering different types and degrees of blocking potency of channel blockers to channel proteins, we have found that the nature of action potential termination process and corresponding ionic current profiles are very distinct from each other. With the increasing blocking affinity, the frequency of action potential spiking falls off exponentially in presence of sodium channel only blockers and dual type blockers having more sodium binding potency than potassium blockers, whereas in contrast, for potassium channel only blockers, dual type blockers having equal or higher potassium blocking affinity with respect to sodium blocking, the spiking frequency initially is enhanced followed by a gradual decrease due to the competition between channel number fluctuation and overall sodium and potassium conductances. Sodium channel blockers tend to shorten the action potential duration while the potassium channel blockers broaden it. The channel gating dynamics are also found to be changed drastically for different types of blockers. The final quiescent state arrival time and the quiescent state membrane voltage profiles show distinct features for different types of channel blockers with different applied external stimulus. Finally, we showed how consistent our results are with the existing literature of experimentally observed channel blocking effects in diverse systems and compared the similarities, dissimilarities and advantages of our model with an existing theoretical drug binding model with Langevin description. Our approach provides a qualitative pathway to investigate the effects of many other types of blocking mechanisms such as closed state, inactivated state blocking with desired level of structural and functional details.